During the operation of an air conditioning or heat pump system, the refrigerant such as freon becomes contaminated by particulate and liquid lubricant such as oil, since oil is very miscible with freon, oil becomes entrained with the freon. After extended periods of time, the refrigerant becomes degraded and requires replacement. Typically, the refrigerant is bled from the system and discarded. As a result, new refrigerant and lubricant has to be added to the refrigerant system.
One attempt to solve this problem has been to devise a refrigerant recovery and purification system. An example of such a refrigerant recovery and purification system is disclosed in U.S. Pat. No. 4,646,527, issued Mar. 3, 1987, to Taylor. The Taylor patent discloses an apparatus having a pair of accumulators serially connected between the compressor and the refrigerant system being evacuated. The output of the compressor is connected to a heat exchanger position within each of the accumulators. The heat exchangers are connected to a condenser. The accumulators, having the heat exchangers positioned therein, function to distill the refrigerant flowing therethrough to separate the oil from the refrigerant. The oil is drained from the accumulators and discarded. Since the oil in the evacuated refrigerant has been removed, a separate oil separator filled with clean oil supplies oil to the compressor to prevent premature failure.
One problem or disadvantage with the above apparatus is that it takes a long time period to evacuate the refrigerant from the refrigerant system. Also, there is recontamination of the refrigerant from lubricant being supplied to the compressor before being stored. Further, it is impossible to calculate the amount of lubricant that needs to be added to the refrigerant system. Draining the refrigerant system of oil and replacing it can be time consuming and costly. Additionally, there is only one mode of operation of the apparatus for separating the lubricant from the refrigerant which limits the apparatus' flexibility.
Another problem arising in the refrigeration industry is that CFC refrigerants are destroying the ozone layer. Recently, several countries signed an international agreement to reduce consumption of CFC refrigerants by the year 2000. This will result in a scarcity of existing CFC refrigerants. Therefore, it will be necessary to reclaim as much of the existing CFC refrigerants as possible.